Pornographic spam has increased by almost 350 percent since June according to statistics released by content security firm, Clearswift.
Pornographic material made up 17.2 percent of all spam, up from 4.8 percent in June, it found.
"This upsurge is similar to the same period last year -- spammers increase their pornographic output during the summer months," said Peter Croft, managing director at Clearswift Asia Pacific.
"The big risk is damage to company reputation when pornographic emails are circulated," Croft added.
Healthcare spam is also on the increase, the majority of which are Viagra advertisements, a concern for pharmaceutical giant Pfizer.
In response to research that indicates 25 percent of men believe the company was responsible for sending Viagra-themed spam, Pfizer has recently begun a legal campaign against spammers peddling potentially counterfeit pills via email and websites.
"Additionally, many of these emails are designed to dupe users into opening viruses that are hidden in web links or zipped attachments," said Croft.
Figures from Clearswift are the result of spam filtered from 20 million users worldwide.